Collaborators: Dept. of ChemE at Pitt, Carnegie Mellon University
Photopolymerization-based 3D printing is a popular method for rapid prototyping and manufacturing. Complex 3D parts can be printed by exposing a photoreactive resin to light in a spatially-selective manner. This project will develop the new concept of wavelength-selective 3D printing wherein both ultraviolet and visible wavelengths of light will be used during polymerization, in order to realize distinct material properties within a 3D object. This award supports a systematic fundamental study to provide knowledge and capabilities for the development of multi-material 3D printing based on wavelength-selective photopolymerization. Numerous applications are envisaged for this technology, ranging from flexible electronics, soft robotics, architected materials, and biological tissues. This project will maintain US leadership in advanced manufacturing, promote scientific progress, and increase national prosperity. It unites researchers with diverse expertise including 3D printing, polymer chemistry, and sensors and robotics. The research will support the training of three graduate students. The University of Pittsburgh is committed to recruiting underrepresented minorities into research. The investigators will conduct outreach at undergraduate and K-12 level on 3D printing technology to attract diverse students towards STEM fields via collaborations with a local public school and science museum.
The new technology aims to address the pressing need for an advanced technology to fabricate 3D multi-material parts rapidly and continuously. In contrast, existing multi-material 3D printing methods use material switch-over methods involving tedious steps of re-alignment and cleaning. Specifically, at present, multi-material photopolymerization printing requires "resin vat changes", which only permits material variation between layers, but not within each layer. This research will fill the knowledge gap on fundamental mechanisms of two-wavelength photopolymerization 3D printing including chemical kinetics, phase transition, thermodynamics, and interfacial mechanics. One important advance of this project is to develop a multiphysics model and simulation method for elucidating the two concurrent and different photopolymerization pathways to realize distinct properties. Another thrust of this project is a highly instrumented platform for in-situ monitoring of the new process, featuring a novel in-situ optical interferometry that can provide otherwise unattainable real-time full-field insights of the unique multi-curing process dynamics. Ultimately, the new process-structure-property relations will be quantified by machine learning of the data from theoretical model simulation, in-situ monitoring, and ex-situ characterization. The research outcomes will facilitate the research on emerging multi-wavelength photopolymerization printing, new photo chemistries and polymers, and novel applications of multi-material 3D printing.